Knife sharpening device



NOV. A ZAHLER KNIFE SHARPENING DEVICE Filed Feb. 24, 1931 fnwavroe: ZAHLEE a ArraeA/Er Patented Nov. 1 5, 1932 GEORGE A. ZAHLER, orcLEvELAND, OHIO" KNIFE snnnrnmiva DEVICE Applicationflled February 24, 1931. Serial No. 517,905. I

. This invention, as indicated, relates to a knife sharpening device. More particularly, it comprises a device for cutting a knife edge .to a degree of'sharpness with file surfaces of special characteristics and position, and

then finishing such, edge with finishing surfaces positionally disposed upon said device with reference to said special file surfaces.

, Heretofore in sharpening knives it has been the general practice to rely on what is termed a sharpening steel, in the form of a tapered bar having cutting grooves etched longitudinally upon its surface, and having a handle at its heavier end, but a true sharpening operation on the knife usually has been carried out as a separate operation on a grinding wheel or with a stone Or file, and a finishing effect has been given the edgeas a separate subsequent operation. The present invention hasfor its principal object the providing of a hand implement which will combine positionally and functionally, related means for sharpening-and finishing a knife edge. The implement, as

a further object, has in view the formation upon. opposite sides of an elongated tapered bar of hardened steel or like suitable material, of surfaces having a cutting effect when stroked alternately by the knife edge in a 39 predetermined directionon 0 posite sides of the implement. It also incluc es the further object of providing an implement which is formed at the intermediate points about its circumferential extent with finishing surfaces such as are usuallyprovided on a sharpening steel by-the etched longitudinallines thereon. Another object of the invention is to provide an article of thecharacter'just described which has its sharpening and finishing surfaces definitely spaced from each other so as to prevent interference and accidental use of two operatively dilferentsurfaces at the same time. a

Another object of the invention is to-provide means on the implement to assist the user in positioning the implement for sharpening action when stroked in a right handed or left handed manner, according to the particular dexterity of the user, and also with means to assist the user iaposiuopingthe finishing surfaces. is y p Another object of the invention is to provide grooves intermediate the sharpening and finishing surfacesiwhich will not only .5

space-said surfaces for independent non-in; terfering use ofeachsuch surface, but will also receive chips. which might otherwise remainin the recesses of the cutting or finishing surfaces. I p Y 6 Other and further objects-of the invention 1 will appear in the courseof the following'de scription. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularlypointed out in the claims. a

The annexed; drawing and the following description set forth certain structures embodying the invention, such disclosed means constituting, however, but severaljof various structural formsin which the principle of the invention maybe. used.

In said annexed drawing: 7 V r I Figure 1 is affront elevation of an imple- 5 ment for use in large establishments, embodying the principles of my inventiomshowing asharpening surface and positioning thumb rest toward the observer,.wit h the guard member shown partially in section; I i

' Figure 2 is a side elevation of the; device shown in Figure 1, showing a finishing surface toward the observer;

Figure 3 is a rear elevation of the device shown in Figure 1 with the companion sharpening surface toward the observer; 1 V V Figure 4is an enlarged sectional view takenalongthe line 4-4 shown in Figure 1, looking in the direction of'the arrows;

Figure 5' is a view, partially'in section, taken along the line 55 shown in Figure 1;

Figurefi is a greatly enlarged longitudinal sectional view taken between the lines6-6 shown in Figure 2; I V 7 Figures 7, 8 and.9 are views similar to those shown. respectively in Figures 1, 2 and v 3, but illustrating an implement primarily for household use; a a

Figure 10 is. an enlarged sectionalview taken along the line 1010 shown in Figure 7, looking in the direction of the arrows Figure 11 is a greatly enlarged longitudinal sectional view taken between the lines 1111, shown in Figure 8; and

Figure 12 is a diagrammatic sectional view showing a modified form of structure. i

As is clearlyshown in the drawing, the device embodying the features of the invention has the general appearance of a standard knife sharpening steel, such as is used in kitchens of large establishments as well as in the household. It should be pointed out, however, that ordinary sharpeningsteels are not limited to use in any particular position or required to be stroked toward or away from the handle. They are universal as to position and direction ofuse In this way these devices as well as all devices of the priorart differ from "the present invention. The device herein set forth is not adapted for universal positioning ordirection of use. It hasa single predetermined position with v. a reference to thesharpening action but may be.

considered of universal positioning with reference to the finishing action although convenience of handling would make it desirable also to use the finishing surfaces in a predetermined position with relation to the adjacent sharpening surfaces.

' The implements for household use are preferably designed to be used by stroking the knife from the handle toward the point of the implement, whereas implements-for use by butchers and chefs in larger establishments are preferably designed to. be stroked from the point of the implement toward the handle, as this conforms to well established customs of the users.

It will be noted from" Figures 1, 2, 3, 7, 8 and '9, that the implement comprises a body portion tapered after themanner of the usual sharpeningsteel and formed'on opposite sides with file'surfaces angularly 'cut so as to have parallel rows of teeth extending in the same direction on said opposite sides. The general structure of the device is shown in Figs. 1, 2, 3, 7, 8 and 9, the first three views illustrating the larger implement designed for use in larger establishments such as hotels restaurants, and shops for the handling of meats and the like, and the last mentioned views illustrating the implement designed for household use. In each ofsaid implements there'is provided a body portion 1 formed preferably of steel suitably treated to have the necessary qualities for the sharpening and finishing of knifeedges. The body portion is tapered toward the free end having a slightly curved surface increasing in degree of curvaturetoward the free end afterthe manner of the standard sharpening steel. The extreme end 2 of thebody portion as well as the portion 3 adjacent the point of attachment of The handle l is preferably formed of wood and is standard form and may be provided with a terminal member 5 suitably apertured to receive a ring 6. The handle is preferably shaped to conveniently fit the hand of the user and adjacent its lower end is formed with a thumb rest 7. The thumb rest 7 is slightly offset from the central axial line of one of the sharpening surfaces as will be hereinafter explained. At a point opposite the positionof'the thumb rest a button 8 is provided to serve as a positioning means for a party using the device in the left hand rather than in therighthand. Between the position of the button and the position of the thumb rest small-headed studs 910 are provided to assist the user in positioning the finishing surfaces. 7 7 v At the meeting point of the handlewith the body portion a guard 11 is provided, said guard as shownin Figures 1 to 7 having a disc-like extension over which is engaged a protecting disc 7 12 preferably formed of aluminum, the edges of which are spun over the edges of the guard 11. By making this disc facing the steel of aluminum or like soft metal, any accidental bringing of the sharpened edge against the guard will not perma nently injure the edge as the metal is'soft enough 'to prevent the breakage of the edge of the blade ofthe knife being sharpened.

As'will more clearly appear from Figures 4 and 5 of the drawing, the-bodyportion'of the implement is formed with four operative surfaces, two of said surfaces-13-1l being file surfaces and two of said surfaces 1516 being finishing surfaces, and each of said surfaces being separated from the adjacent surfaces by a longitudinal groove 17. The groove may take the form of a U-shaped groove, as is shown more particularly in Figures 4 and 5, or may take the form of a V-shaped groove 18, as is shown moreparticularly in Figure 10-. The sharpening surfaces 131l are preferably file surfaces with the cutting edges formed with parallel rows of teeth extending from'left to right, as is more particularly shown in Figure. 1. The teeth-on opposite sides of the implement each extend in the same angular direction, being parallel to each other, although when the implement is reversed, the direction of the teeth on the reverse side 14: would be from right to left as in an upward direction, as is clearly shown in the drawing. In the space marked 66 in Figure 2, the parallelism of the cutting teeth of the surfaces 131 1 isclearly.

the handle are finished as a smooth surface. *clined toward the free end ofthe implement ice so that cutting actiontakes place as the knife.

edge is moved in" a'direction toward the faces. are angularly' directed toward the handle portion of the implementso that as the knife blade'is stroked over the sharpening surfaces in a directiontoward the free end of the implement suitable cutting action willtake place. I 5

In each instance theintermediate surfaces 1516 areprovided with shallow longitudinal grooves providing what is known as etched surfaces.

The difference in the positioning of the file surfaces is clearly brought out in Figures 7 to 9, as compared with Figures 1 to 3. As has been stated the grooves of the file surface extend from left to right in an upward in an upward direction in Figure 7, the grooves being preferably at an angle of about 20 to the horizontal. They extend parallel to each other as is shown in the space marked 11-11 in Figure 8 and preferably on the reverse side of the implement, as is shown in Figure 9, the grooves of the cutting surface extend from left to right in an upward direction instead of from right to left in an upward direction as shown in Figure 3.

The grooves 17 and 18 or any other configuration of groove which may be found desirable not only serve to space the surfaces so that a knife blade applied to the intermediate surfaces will not accidentally contact with an adjacent surface having another operative effect upon the knife ed e, but also serve as a means for receiving the c ips which accumulate in the teeth of the file surfaces or the longitudinal etchings of the finishing surfaces. It will be noted that the edges of the surfaces adjacent the grooves are rounded so as to prevent any cutting action upon the knife edge by the extreme edges of either type of surfaces.

The form of construction illustrated in Fi ure 12 provides for the application of the knife edge to each of the sharpening surfaces at a central point of such surfaces which is slightly in advance of a vertical plane extended through the implement. This is accomplished by forming the finishing surface 21 at the front of the implement of lesser extent circumferentially of the body than the rearward finishing surface 22. Thus the grooves 2324 will be closer to each other than the true 90 position, while the grooves 25-26 will be spaced from each other more than a distance of 90 on the circumference of the body of the implement. The knife edge accordingly, when stroked upon the cutting surface, will be brought against the center of the cutting edge at a point 28 on one side and at a point 29 on the opposite side with the knife edge exactly tangential to the direction in Figure 1, and from right to leftcenter of each of saidsurfaces fromlapcominon point of movement in front of sa1d implement.

The manner using the implement has already been indicated in connection with the description of its construction; The implement obviously may'be held in variousipositions but the usual method of sharpening a knife is carried out by holding the implement in the left hand with the thumb on the thumb rest and with the point of the implementextending' at a sharp upwardang-le. The knife to. be sharpened is then held in the'right hand and wherrthe larger implement shown in Figures 1' to 3*;is used, the knife is V stroked downwardly across the cutting surfaces alternately until the;dfes'ired sharpness ofedge is obtained and-thereafter the implement is rotated throughan angle of in either direction andthe knife edge againis preferably stroked .downwardly alternately on the opposite sides of'the finishingsurfacesfluntil the desired finish'of the edge is produced.

When, the household typeof implement is used, the implement is held at a slight angle to the horizontal and the-knife is stroked alternately, on the opposite edges of the sharpening surfaces towardthe point of the implement, until the desired-cutting edge is produced and the implement is then rotated through an angle of 909 and the knife is then i stroked preferably toward the point of the implement until the desired finish to the edge of. the same. is produced.

Thus it; will be noted that the implement must in each instance be held at a particular position and stroked in a particular direction in order to produce thesharpening orcutting effect upon theedgeof the blade of the knife.

The finishing effect may be produced by stroking the knife differently; or from either side but it isquite obvious that a person us ng the device in a. certain manner for the sharpening operation will use substantially the same stroke upon the other surface for the finishing operation. c v I When the device is to .be used by aleft handedperson the implementobviously is held in the right hand with the thumb of the user upon the buttonB- insteadof on the thumb rest'7, all'of the other operations being substantially the same, the knife being stroked against the body ofthe implementby the use of theoperators lefthand and the direction of stroke, the same being-toward the handle portion in case of the device shown in Figures 1 to 3, and toward thefreeend ofthe device in case of a household implement such as is shownin Figures 7 09. 7

Other modes of applying the'prin'ciple of my inventio'umay be employed instead of the one explained, change beingmade as: regards the structure herein disclosed, provided 'the means stated byany of the following claims or the equivalent of such stated means be emand being disposed substantially opposite each other and being uni-directional in use, said surfaces having a preliminary cutting effect, and two other of saidoperative sursaid two operative surfaces being spaced cireumferentially a distance of less than 180 onthe side toward the position of the article to be operated upon suflicient to bring said article to be sharpened tangentially against the centralportions of each of said uni-directional operative surfaces, from a single relatively fixed point of support for said article to be sharpened. I

Signed by me this 9th day of February,

' GEORGE A, ZAHLER.

faces disposed substantially opposite each other and 7 intermediate said first-named two surfaces, said intermediate surfaces having a structure to produce a finishing effect.

2. A knife sharpening device having in combination an elongated body member substantially circular in cross-section presenting a plurality of radially spaced transversely curved longitudinally extending operative surfaces, two of said operative surfaces having rows of file teeth inclined in one direction only, and the teeth of said two operative surfaces being parallel to each other, and being disposed substantially opposite each other and being uni-directional in use and each of said surfaces being spaced for independent use to its extreme margins from any adjacent operative surfaces by means of longitudinally extending grooves with roundededges.

3. A knife sharpening device having in combination an elongated body member presenting a. plurality of radially spaced longitudinally extending operative surfaces, two of said operative surfaces having rows of file teeth inclined in one direction only, and the teeth of said two operative surfaces being parallel to each other, and being disposed substantially opposite each otherand being uni-directional in use and comprising segments of a substantially cylindrical surface, 5 i

the central longitudinal axial lines of each of said two operative surfaces being spaced circumferentially a distance of less than 180 on the side toward the position of the article to be operated upon, and a distinctive thumb contact element for determining the single position for using said sharpening surfaces.

4. A knife sharpening device having in combination an elongated body member presentinga plurality of radially spaced longitudinally extending operative surfaces, two of said operative surfaces having rows of file teeth inclined in one direction only, and the teeth of said two operative surfaces being parallel to each other, and being disposed substantially opposite each other and; being uni-directional in use and comprisingsegments of a substantially cylindrical surface, the central longitudinal axial lines of each of 

